Snare Island Penguin
| Snare Island Penguin | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
_large.jpg)
Snare Island Penguin ( Eudyptes robustus ) |
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Eudyptes robustus | ||||||||||
| Oliver , 1953 |
The snares penguin ( Eudyptes robustus ), also Snares Dickschnabelpinguin simple or snare penguin called, is a penguin , the only on the Snare Islands south of New Zealand breeds. It belongs to the genus of the crested penguins . No subspecies are distinguished.
The snare island penguin is classified as endangered ( vulnerable ) by the IUCN , as the species only breeds on a small group of islands. Extraordinary events can therefore have a very rapid and very strong impact on the entire portfolio.
Appearance
The snare island penguin reaches a body size between 51 and 61 centimeters. Males are slightly larger and heavier than females. It is the only noticeable sexual dimorphism and is especially noticeable when breeding pairs are observed. Males weigh between 2.6 and 3.4 kilograms. Females reach a weight of 2.5 to 2.8 kilograms. The weight is subject to significant seasonal fluctuations. Sexually mature snare island penguins generally have the lowest weight during the rearing of the chicks.
The plumage of adult snare penguins is black on the chin, throat, cheeks, back and wings . Starting from the beak , a band of pale to bright yellow feathers runs on both sides of the head above the eyes to the back of the head. The upper part of the body is bluish black when the plumage is freshly moulted. It has faded to a brownish tone in adult birds that are about to moult. The wings that have been transformed into fins are also blue-black on the upper side, the underside of the fins is whitish with a dark spot on the tip of the fin. The long and strong beak is orange-brown. At the base of the beak there is a narrow strip of featherless pink-white skin that forms a conspicuous triangle at the base of the beak. The iris is noticeably reddish brown in most individuals. Feet and legs are predominantly pink, the soles, the tips of the webbed feet and the back of the legs are black-brown.
Fledglings can be distinguished from adult birds by the differences in plumage up to two or three years of age. Until the end of their first year of life, they are significantly smaller than the adult snare island penguins. The head of feathers is only hinted at. The chin is whitish to gray and only black in individual individuals. The featherless skin on the base of the beak is already there, but not as noticeable as in the adults. The beak is duller in color and less strong. Two- and three-year-old birds are very similar to adults, but their feathers are also much shorter than that of adults.
It can be confused with all other types of crested penguins . In wet birds, in which the head of feathers rests against the head, the possibility of confusion with the crowned penguin and the thick-billed penguin is particularly great. The unmistakable characteristics of the snare island penguin are, however, the combination of the strong and thick beak and the featherless skin at the base of the beak.
distribution
The Snare Island Penguin only breeds on the Snare Islands , which are about 120 km south of the South Island of New Zealand. They are absent in the area of their breeding colonies from May to August. They then migrate to other ocean regions; During this time, the birds can occasionally be found on the coast of mainland New Zealand ( South Island ). Snares penguins have also been sighted on the Chatham Islands , Macquarie Island and Tasmania . The maritime distribution area extends over the extreme southwest of the Pacific.
Diet and predators
The diet of the snare island penguins has so far only been examined very superficially. Presumably they mainly eat krill but also small fish and squid . Based on the times that penguins are present in their breeding colonies, it can be concluded that they mainly look for food during the day and stay near their breeding colonies during the breeding season. Most of the breeding birds are also in the colonies at night. They are often observed in small groups and are often socialized with other sea birds such as albatrosses . The predators of the snare island penguin are marine mammals such as New Zealand fur seals , New Zealand sea lions and killer whales as well as sharks .
Breeding and rearing
The Snares Island penguins breed exclusively on four islands of the Snares Archipelago. Breeding colonies can be found on flat, muddy coastlines and gently sloping, rocky hills. The breeding colonies are up to 600 meters inland and 70 meters above sea level. The breeding pairs land on rocky stretches of coast on the more protected eastern sides of the islands. They nest in clearings or under trees and shrubs of the genera Olearia and Brachyglottis . They also use thickets of Hebe on the edge of forests and also breed on exposed ledges and between rubble. Basically, snare island penguins show a similar social behavior as the other crested penguins, but compared to the thick-billed penguin and the rockhopper penguin they live a little more socially. Aggressive gestures include threatening with an open beak, often making hissing sounds. Occasionally, they will also raise their fins, bend forward, and take a few steps toward their opponent. They shout loudly, trumpeting. In direct disputes, they occasionally grab each other by the beaks.
In August, the Snares penguins begin with violent turf wars in the breeding area , the forests of the islands, with the colony formation . The nests are close together and the colonies are small to medium-sized. They include between 160 and 1,900 pairs. There are two nests per square meter, the nest hollow is on average 35.7 centimeters away. The nest is a shallow hollow that is occasionally found on a small platform made of twigs, twigs, and mud. It is mainly erected by the male.
During the breeding season in September and October, the female lays two eggs four to five days apart , with the first usually being smaller. It is usually only 77 percent of the mass of the second egg. Unless one of the two eggs is lost during the incubation (e.g. during the breeding routine or attacks by neighboring penguins), two chicks hatch after an incubation period of 31 to 37 days. The breeding season can be divided into three phases. During the first phase of about ten days, the two parent birds breed alternately. Then the female parent bird alone incubates for a period of twelve days and then the male takes over the brood until the chicks hatch. The hatching of the chicks is largely synchronized within the colony. While eggs are laid within a colony over a period of 23 days, the chicks hatch over a period of 14 days. The hatching interval between the two eggs of a clutch is between 0 and four days. At least one chick hatches in around 93 percent of the clutch and the second chick in 63 percent of the clutch. The newly hatched chick is guarded by the male alone for a period of three weeks. The female probably brings in food for the young on a daily basis. Only one of the two chicks in a clutch survives. It is usually the chick of the first egg that starves to death within ten days because it is not being fed by the parent birds. There is only one documented case so far in which Snare Island penguins raised both young birds. At three to four weeks the young form larger groups, at 75 days they moult.
The current population is estimated by the IUCN to be 60,000 sexually mature individuals.
supporting documents
literature
- Tony D. Williams: The Penguins . Oxford University Press, Oxford 1995, ISBN 0-19-854667-X
Web links
- Eudyptes robustus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 2 of 2009.
- eudyptes.net (rudimentary) blog of a research project on the snares penguin
Single receipts
- ↑ BirdLife Factsheet on the Snare Island Penguin , accessed November 17, 2010
- ^ Williams, p. 200 and p. 202
- ^ Williams, p. 202
- ^ Williams, p. 201
- ^ Williams, p. 202
- ^ Williams, p. 203
- ↑ Williams et al., P. 202
- ^ TC Lamey: Snares penguin in the Falkland Islands. In: Notornis. 37 (1), 1990, p. 78
- ↑ a b c Daniel Gilpin: Penguins . Parragon Books Ltd., ISBN 978-1-4075-0629-6 .
- ^ Williams, p. 204
- ^ Williams, p. 203
- ^ Williams, p. 204
- ^ Williams, p. 204
- ^ Williams, p. 205
- ^ Williams, p. 205
- ↑ BirdLife Factsheet on the Snare Island Penguin , accessed November 17, 2010